Polymerization of alpha olefins



Patented Mar. 14, 195o 2,500,244 POLYMERIZATIGN F ALPHA OLEFINS Harry G. Doherty, Woodbury, N. J., assigner to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application April 2l, 1949,

- Serial No. 88,895

Claims. (Cl. 26o-683.1)

This invention has to do with the production of synthetic lubricants and, more particularly, has to do with the production of these lubricants by a thermal, non-catalytic treatment of certain types of normally liquid oleflns at high temperatures.

In a copending application, Serial No, 761,716, led on July 17, 1947, abandoned in favor of application Serial No. 104,932, filed July 15, 1949, a process has been described for the preparation of synthetic lubricants of excellent character, namely, high viscosity index, relatively low pour point and satisfactory stability. The process there described involves a thermal, non-catalytic conversion of normal, alpha mono-olefins having between about six and about twelve carbon atoms per molecule. Temperatures of operation range from about 500 F. to about 750 F., preferably from about 600 F. to about 700 F.

Although good yields of these desirable synthetic lubricants are obtained by so treating the aforesaid oleiins at temperatures lower than about 700 F., the residence or reaction times required to produce commercially feasible yields is excessively long. As disclosed in the aforesaid copending application, however, yields of synthetic lubricants and the viscosity indices thereof 1 diminish substantially as the temperature is raised above 700 F. and secondary reactions are initiated. Secondary reactions which are considered to be involved at the higher temperatures are:

(l) Degradation or cracking begins, as evidenced by decrease in oil yields;

(2) Cyclization begins, -as evidenced by a deeline in viscosity index with accompanying increase in gravity and refractive index; and

(3) Volatile non-oily components of the reaction mixtures become progressively more saturated, as indicated by a decrease in bromine addition number and, therefore, less suitable for recycling for further conversion.

As a substantial improvement over the aforesaid process, it has now been discovered that synthetic lubricants possessing the combination of desirable properties referred to above, can be produced at temperatures greater than about 700 F. in goodv yields and in relatively short time periods. The present process comprises treatment of a normal, alpha mono-olefin having be- .Jol

tween about six and about fourteen carbon atoms per molecule, in the absence of a catalytic material and in the presence of a minor and effective proportion of a cyclic hydrocarbon, at temperatures greater than about 700 F. and not substantially above about 900 F. for relatively short reaction or residence times.

Normal, alpha mono-olefins ing from eight to twelve carbon atoms, withV decene-i representing a particularly desirable olefin. It will be clear lfrom the foregoing examples that an alpha olen may also be referred to as a l-oleiin.

Not only may the mono-olens of the aforesaid character be used individually in this invention, but they may also be used in admixture with each other. In addition, olefin mixtures containing a substantial proportion of such monoolens may be used. Preferred of such mixtures are those containing a major proportion of a l-oleiin or of l-olens. Representative of such mixtures are those obtained by the cracking of param waxes and other paraiin products; those obtained from the Fischer-Tropsch and related processes.

These hydrocarbon mixtures may contain, in addition to the l-olefn or l-oleiins, such materials as: other oleiins, parains, naphthenes and aromatics.

In many instances, in commercial operation, it will be found desirable to use technical grades of l-olefins. Mixed olefinic materials derived from thermal cracking of hydrocarbon wax or from the Fischer-Tropsch process `constitute satisfactory charging stocks. In this connection, it must be noted that itis suspected that substantially straight chain l-oleiins, that is, l-oleilns in which the length of the side chain (or chains) is short relative to the length of the main chain, and in which the side chain (or chains) is not adjacent 3 to the double bond, are also suitable, although less advantageous charge stocks for the purpose of the prent invention. In view of the unavailability4 of such olefins, however, no test data can be addnced to coniirm this suspicion.

Oldie hydrocarbons The cyclic materials used herein to inhibit or retard secondary reactions may be aromatic, naphthenic or other carbocyclic hydrocarbons. Typical of such hydrocarbons are benzeneI toluene, xylenes, propyl benzenes, octyl benzenes, etc.;

. naphthalene, l-methyl -naphthalene, Z-methyl naphthalene, polymethyl naphthalenes and naphthalenes having longer alkyl chains; cyclopentane, methyl cyclopentane and the like; cyclohexane, methyl cyclohexane, dimethyl cyclohexane, ethyl cyclohexancq and the like; tetralin, and the like. Hydrocarbon mixtures rich in such cyclic materials may also be used, in place of the individual hydrocarbons. Representative of such mixtures are coal tar fractions, straight run and cracked (non-catalytically and catalytically) pethat each group be limited to not more than two carbon atoms- In the same connection, the position of a substituent group upon the cyclic nucleus is influential, as demonstrated by the appreciably greater eilicacy of 2-methyl naphthalene in contrast to I-methyl naphthalene.

With regard to the concentration of the cyclic inhibitor or retardant', minor amounts as low as about 0.1 per cent to 20 per cent or more may be used. Preferably, however, minor amounts of the order of about one to about ilve per cent of the total charge are most effective. A s shown in the illustrative examples hereinafter, the eiiectiveness of the various cyclic materials varies to some extent- For example, three per cent of benzene is excellent; whereas, live per cent or more of toluene is required to obtain a similar degree of improvement and three per cent of toluene provides considerably less improvement. proper concentration will depend largely on inhibitor selected and conditions used.

Reaction conditions The relatively high temperatures and relatively short reaction times of operation used in the present process, vary inversely with each other. When temperatures of the order of about 'TO0-'750 F. are used, reaction times are preferably from about three to about one hour; whereas with temperai tures of about 800 F., about one to about onehalf hour reaction time is satisfactory. Operation at about 850 F. is attended by reaction times of one-half to one-quarter hour.

The operating temperatures and reaction times are critical features herein, as are the concentration and structure of the cyclic inhibitor previously discussed. As a further note relative to inhibitor structure, with temperatures of about The 850 F., it has been found that an unsubstituted f cyclic compound or one containing only one normal, short-chain alkyl group is more emcacious.

This is particularly illustrated by benzene, cyclohexane and their alkylated derivatives.

The foregoing operating conditions appear to be of importance in the present process, other conditions having less influence. Pressure, for

example, does not appear to be critical. It may range from about 100 to about 4,000 pounds per square inch, or even higher.

As indicated above, the present process is a thermal, non-catalytic process related to that described in said copending application Serial No. 761,716. The process is described as non-catalytic inasmuch as polymerization or condensation catalysts are not used. For example, Friedel- Crafts type catalysts such as aluminum chloride have hitherto been used to polymerize olens, under conditions-'differing considerably from those recited above. It is with this in mind that the present process is described as "non-catalytic.

Examples In order to illustrate the principles of this invention, the results of a series of typical, and non-limiting, conversions are set forth in tabular form in the several tables shown below. These conversions were carried out in rocking-type bombs (American Instrument 0o.). The oleiins and cyclic inhibitors were charged to the bombs. The bomb heads were secured and the bombs were ushed with nitrogen to displace air present therein. The bombs were then heated (while rocked) to the desired temperature for the desired length of time. Thereafter, the bombs were either cooled and discharged, or discharged immediately through a condensing system while the reactants were still at the reaction temperature.

It should be noted that the reaction times, recited as Time, Hours in the tables, represent the time intervals during which the bombs were maintained atv the desired temperature, and do not include the time intervals necessary to heat the bombs and their contents to the desired temperature, and do not include the time intervals necessary to cool the bombs after heat to the bombs has been discontinued. In general, about one and one-half hours are required to raise the temperature from Bil- F., to '750 F., and about eight hours to cool thereafter to 60-80 F., in runs such as shown in the tables. However, since it has been shown in said application Serial No. '761,716 that substantially no polymerization occurs below 500 F., these times are of little significance. The examples given in the tables were made under directly comparable conditions. The condensation products discharged from the bombs were vacuum topped to remove any unreacted hydrocarbon material and. any relatively low boiling products, and then were ltered, as in the runsshown in the tables. To distinguish the condensation products from the distillate fractions thereof, the rened oils are identified as residual oils. The latter term identies the oils from which unreacted materials and products oi intermediate boiling range have been separated.

All of the tests and analyses to which the residual oils in the tables were subjected are well known standard tests. In this connection, it will be noted that the designation N. N." refers to the neutralization number, which is a measure of the acidity of the oil.

In Table I below, several comparable runs are is used. While benzene is greatly superior to shown for conversions of decene-l with and toluene when used in three per cent concentrawithout cyclic inhibitors. tion, the two cyclic compounds are of the same TABLE I Run No l 2 3 4 5 6 7 8 9 olefin Decana-1.. Decene-l-- Decene-l.. Decenei... Decn -1 D i.

Parts by weight.. 74 40o 38s aso ses 380 38s. .e.. sagem. Cyclic Inhibitor Benzene... Toluene... Toluene... Toluene.-. Xylene. Ethylb Parts by Weight 20 12 12, omene' Wt. Percent 'lotal 5 Charge.

Temperature, "F Reaction Time, Hrs.. Max. Pressure, p. s. l. g Residual Oil:

Yield, Wt. Perccni Ole- 30.0. Vil? Charged.

ll6.4. Viscosiiy@m0 F., Cs 2'.80. Viscosity @210 F., Cs.. 4.29. Pour Point., "F +10 +15 Specific Gravity 411.8630.-." Y .5 Color (Lovibond) Carbon Residue (Ramsbottom) Run No 10 l1 .2 13 14 15 16 Olelin Decene-l Decene-1 Deccne-l Decene-l. Decene-l.

Parts by Weight-- 388 388 388. Cyclic Inhibitor Isopropyl t-butyl ben- Sec. Axnyl Sec. Amyl Naphthalene.. 2-methyl l-meth lbenzene. zene. benzene. benzene. napht alene. Parts by Weight 12 12. l2 12 12. Wt. Percent Total 3. T Charge. 0F

emperature, 750. Reaction Time, Hrs 3 Max. Pressure, p. s. i. g... 1500, Residual Oil:

Yield, Wt. Percent 24,7,

Oleiin Charged. -V. L-: 114.0. Vicosity 100 F., 31.44.

s. Vieoslty 210 F., 5.35.

s. Pour Point, F Specific Gravity N. N Color (Lovibond)- .Carbon Residue (Ramsbottom) Run No 1T 18 19 2O 2l. 22 23 Olefm Decene-l Decene-l Deccne-l Dccene-l Decene-l Deeene-l Decene-l,

Parts by "eghL 388 388 380 380 u 3c8 380. Cyclic Inhibitor Aromatic Cyelohexane Cyelohexanc.. Methyl Cy- Dimethyl Cy- Ethyl Cyclo- Methyl Cy- Stock.l clohexane. clohexane. exane. clopentane. s Pari-s by \Veight 12 12 20 20 20 12 20, Wt. Percent Total l 5.

Charge. Temperature, F 750. Reaction Time, Hrs 3. Max. Pressure, p. s. i. g... 800. Residual Oil".

Yield, Wl. Percent 43.5.

Olein Charged. V. L.. 128.3. C Ic0 F., 23.54 20.05.

s. Vicosity 210 1"., l4.72 4.17.

s. Pour Point, F.... +5 +20. Specic Gravity. 0.8443 0.8493. N.N 0.1 0.1.v Color (Lovibond). 4 17. Carbon Residue 0.02.. 0.05.

(Ramsbottom). l

l Aromatic Stock is a refinery eut of the following approximate composition: 88% dimethylnaphthalene; 0.5% fluorenc; 2.5% phenanthrau cene. It may contain some trimethylnaphthalenes.

The results shown above in. Table I demonorder of effectiveness in ve per cent concentrastrate the varying degrees of improvement realtion. ized with certain cyclic inhibitors. For example, Xylene and ethyl benzene are effective in three runs 1-4 reveal the substantial improvement in per cent concentration, as shown by runs 8 and 9. yield and V. I'. obtained with benzene incorpo- 70 Runs 1013 reveal that three per cent is an inrated in the decene-l charge. Runs 5-7 were siicient concentration when benzene carries as made with toluene as the inhibitor, and indicate a substituent an alkyl group of three or more that three per cent of toluene is insuilcient to carbon atoms. bring about improvement. Yield and V. I. are Run 14 reveals that three per cent is an inenhanced, however, when ve per cent of toluene 75 sufficient quantity when naphthalene is the cyclic 7 material.` In contrast, Run indicates that 2. methyl naphthalene is excellent as an inhibitor when used in three per cent concentration. Surprisingly, l-methyl naphthalene is ineffective in 8 generally characterized by phosphorus. sulfur, nitrogen, etc., content; representative of such materials is a phosphorusand sulfur-containing reaction product of pinene and Pass. Typical three per cent concentration, as shown by Run 5 detergents which may be so used are metal salts 16. Dimethyl naphthalenes are shown to be ot alkyl-substituted aromatic sulfonic or careftectiveinRxm 17. boxyllc acids, as illustrated by diwax benzene Runs 18-22 reveal the substantial improvebarium sulfonate and barium phenate, barium ment in yield and V. I. obtained with naphthene carboxylate of a waX-substitutedphenol carboxylic inhibitors. Runs 19-21 demonstrate that yield lo acid. Extreme pressure agents are well known: and V. I. are further enhanced when methyl illustrating such materials are numerous chlorine cyclohexane is used in iive per centvconcentraand/or sulfur containing compositions, one such tion. material being a chlornaphtha xantbate. Sill- Considering the results in Table I further, it cones, such as dimethyl silicone, may be used to wi1l be noted that, in three to ve per cent con- 15 illustrate foam suppressing compositions. Viscentration, the most eiiective aromatic inhibicosity index improving agents which may be used tors are benzene, xylenes, ethyl benzene, cycloare typified by polypropylenes. plyisobutylenes, hexane," methylcyclohexane, dimethylcyclohexpolyacrylate esters, and the like. ane, and ethylcyclohexane, Z-methyl naphthalene Contemplated also as within the scope of this and dimethyl naphthalenes. 20 invention is a method of lubricating relatively The serios of runs set forth in Table II serve moving surfaces by maintaining therebetween a to indicate the influence of higher temperature film consisting of any of the aforesaid oils. upon the conversion of decene-il and upon the It is to bepunderstood that the foregoing deactivity of cyclic inhibitors. l scription and representative examples are non- Table II Run No l 2 3 4 5 Olen Partsb Cyclic Inhi ltor Parts by Weight Wt. Per Cent Total Charge- Temperature, F- Reaction Time, Hrs Max. Pressure, p. s. i. g

Residual Oil:

Yield, Wt. Per Cent Oleiin Charged 6.3 4.7. V. I. of Polyma' 0i] Below Zero... Below ZeroL...

Viscosity Q 100 F., Cs i738 195.6 Viscosity Q 210 F., Cs 24.87 10.86 Pour Point, "F Specific Gravity N. N 0.8 Color (Lovibond) Carbon Residue (Ramsbottom) 2.7

In Table II, Runs 1-3 show the high degree of improvement obtained with benzene. Run 4 shows a similar improvement obtained .with methyl cyclohexane. Secondary-amyl benzene is shown to be ineffective in three per cent concentration at 850 F., the result being similar to that obtained at 750 F.

As will be evident from the data presented above in Tables I and II, the condensation products of this invention are highly desirable lubricants per se. They are also of considerable value as blending agents for other lubricating coils. They impart desirable viscosity index (V. I.) and pour point characteristics to the oils in combination therewith, for, as indicated above, they have advantageous viscosity index and pour point properties. In short, the synthetic oils find utility in "upgrading" other lubricants. Typical oils with which the synthetic oils may be blended are mineral oils such as are normally used in internal combustion and turbine engines. When so blended, the synthetic oils may comprise the major proportion of the iinal blended oil, or may even comprise a minor proportion thereof.

One or more of the individual properties of the synthetic lubricants of this invention may be further improved by incorporating therewith a small, but effective amount, of an addition agent such as an antioxidant, a detergent, an extreme pressure agent, a foam suppressor, a viscosity index (V. I.) improver, etc. Antioxidants which may be used are well known in the art, and are limiting and serve 'to illustrate the invention, which is to be broadly construed in the light of the language of the appended claims.

I claim:

l. The method for preparing a viscous oil from a normal, alpha mono-olefin having from about six to about fourteen carbon atoms per molecule, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olefin in the presence of a minor and effective amount of a cyclic hydrocarbon, at a temperature greater than about '100 F. for a period of time from about one hour to about three hours, and less than about 900 F. for a period of time from about one-half hour to about one-quarter hour.

2. The method for preparing a viscous oil from a normal, alpha mono-olen having from about six to about fourteen carbon atoms per molecule, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisinng essentially of said oleiin in the presence of a minor and effective amount of a cyclic hydrocarbon, at a temperature greater than about 750 F. for a period of time from about one hour to about three hours, and less than a temperature of about 850 F. for a period of time from about one-half hour to about one-quarter hour.

3. The method for preparing a viscous oil from a normal, alpha mono-olefin having from about eight to about twelve carbon atoms per molecule,

1| which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olefin in the presence of aminor and effective amount of a cyclic hydrocarbon, at a temperature greater than about 700 F. for a period of time from about one hour, to about three hours, and less than about 900 F. for a period of time from about one-half hour to about onequarter hour. Y

4. The method for preparing a viscous oil from n-decene-l, which comprises: thermally and noncatalytically heating a hydrocarbon charge consisting essentially of said olei'ln in the presence of a minor and effective amount of a cyclic hydrocarbon, at a temperature greater than about 750 EF'. for a period of time from about one hour to about three hours, and less than a temperature of about 850 F. for a period of time from about onehalf hour to about one-quarter hour.

5. The method for preparing a viscous oil from a normal, alpha mono-olefin having from about six to about fourteen carbon atoms per molecule, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olen in the presence of a minor and effective amount of a cyclic hydrocarbon selected from the group consisting of benzene, xylenes, ethylbenzene, cyclohexane, methyl cyclohexane, dimethyl cyclohexane, ethyl cyclohexane, 2-methyl naphthalen'e and dimethyl naphthalenes, 'at a temperature greater than about 700 F. for a period of time from about one hour to about three hours, and less than about 900 F. for a period of time from about one-half hour to about one-quarter hour.

6. The method for preparing a viscous oil from a normal, alpha mono-olefin having from about six to about fourteen carbon atoms per molecule, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olefin in the presence of a minor and effective amount of a naphthene, at a temperature greater than about 700 F. for a period of time from about one hour to about three hours, and less than about 900 F. for a period of time from about one-half hour to about one-quarter hour.

7. The method for preparing a viscous oil from a normal, alpha mono-olen having from about six to about fourteen carbon atoms per molecule, which comprises: thermally and non-catalytically heating a hydrocarbon charge consisting essentially of said olen in the presence of a minor and effective amount, from about one per cent to about five per cent, of a cyclic hydrocarbon, at a. temperature greater than about 700 F. for a period of time from about one hour to about three hours, and less than 'about 900 F. for a period of time from about one-half hour to about onequarter hour.

8. The method for preparing a viscous oil from n-decene-l, which comprises: thermally and noncatalytically heating a, hydrocarbon charge consisting essentially of n-decene-l in the presence of about three per cent by clohexane, at about 750 F. for about three hours.

9. The method for preparing a viscous oil from n-decene-1, which comprises: thermally and noncatalytically heating a hydrocarbon charge consisting essentially of n-decene-I in the presence of about three per cent by weight of xylene, at about 750 F. for about three hours.

10. The method vfor preparing a viscous oil from n-decene-l, which comprises: thermally and noncatalytically heating a hydrocarbon charge consisting essentially of n-decene-l in the presence of about three per cent by weight of benzene, at about 850 F. for about one-half hour.

HARRY G. DOHERTY.

. REFERENCES CITED The following references are of record ln the le of this patent:

UNITED STATES PATENTS Number Name Date 2,450,451 Schmerling Oct. 5, 1948 OTHER REFERENCES weight of methyl cy-I Certificate of Cection Patent No. 2,500,244 Mam 14, 1950 HARRY G. DOHERTY It is hereby certied that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 70, for Runs 1013 read Runs 10-13; column 7, line 55, for the Word coils read oils;

and that the Said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Olce.

Signed and sealed this 19th day of December, A. D. 1950.

THOMAS F. MURPHY,

- Assistant 'ommz'ssz'oner of Patents, 

1. THE METHOD FOR PREPARING A VISCOUS OIL FROM A NORMAL, ALPHA MONO-OLEFIN HAVING FROM ABOUT SIX TO ABOUT FOURTEEN CARBON ATOMS PER MOLECULE, WHICH COMPRISES: THERMALLY AND NON-CATALYTICALLY HEATING A HYDROCARBON CHARGE CONSISTING ESSENTIALLY OF SAID OLEFIN IN THE PRESENCE OF A MINOR AND EFFECTIVE AMOUNT OF A CYCLIC HYDROCARBON, AT A TEMPERATURE GREATER THAN ABOUT 700*F. FOR A PERIOD OF TIME FROM ABOUT ONE HOUR TO ABOUT THREE HOURS, AND LESS THAN ABOUT 900*F. FOR A PERIOD OF TIME FROM ABOUT ONE-HALF HOUR TO ABOUT ONE-QUARTER HOUR. 